Abstract
Developing organic friction materials for brake lining is a complex task. Friction materials for brake lining contain four classes of ingredients: binder, fibers, friction modifiers and fillers, with some overlap of functions at times. The combination of several ingredients in right amount and acting synergistically is one key to develop desired friction material for a particular braking application. On the other side, friction material efficiency is highly dependent of the hot-molding elaboration process, which affects the lining microstructure and properties. Large efforts have been made to develop these organic friction materials. However, the lake of understanding of the link between material formulation, elaboration process and brake-induced phenomena limits material braking performance improvement that is mainly drive by the know-how and empirical experience of manufacturers.
The present study concerns the hot-molding process of elaboration of a phenolic-resin based composite lining for truck drum brake. In order to limit the complexity of the composite material and consequently of couplings between formulation, process and friction-induced phenomena, a specific formulation is developed with a reduced number of ingredients, derived from an industrial formulation. Temperatures and durations of curing are evaluated considering differential thermal analysis (DTA) of the binder resin and a characterization of its glass transition using a torsional test performed on a KINEMAT device. Lining elaboration with the selected hot-molding parameters is studied on the industrial line process, and friction materials are characterized and compared in terms of tribological behavior and wear on both continuous and braking tribometers.
KEYWORDS -brake lining process, organic composite pad, curing parameters, braking performances